Rayleigh wave dispersion measurements reveal low-velocity zones beneath the new crust in the Gulf of California
Abstract
Rayleigh wave tomography provides images of the shallow mantle shear wave velocity structure beneath the Gulf of California. Low-velocity zones (LVZs) are found on axis between 26 and 50 km depth beneath the Guaymas Basin but mostly off axis under the other rift basins, with the largest feature underlying the Ballenas Transform Fault. We interpret the broadly distributed LVZs as regions of partial melting in a solid mantle matrix. The pathway for melt migration and focusing is more complex than an axis-centered source aligned above a deeper region of mantle melt and likely reflects the magmatic evolution of rift segments. We also consider the existence of solid lower continental crust in the Gulf north of the Guaymas Basin, where the association of the LVZs with asthenospheric upwelling suggests lateral flow assisted by a heat source. These results provide key constraints for numerical models of mantle upwelling and melt focusing in this young oblique rift.
Additional Information
© 2015 American Geophysical Union. Received 9 FEB 2015; Accepted 2 MAR 2015; Accepted article online 5 MAR 2015; Published online 30 MAR 2015. We thank L. Ferrari and S. Bryan for their review and useful discussions on the tectonics and volcanism in the southern Gulf of California, J. Contreras-Pérez for his thoughtful review of the manuscript, and V. Langenheim for providing the magnetic potential data for the study region. We also thank an anonymous reviewer and the Editor for their help in improving the final manuscript. Some figures were generated using the GMT software [Wessel and Smith, 1998]. The Editor thanks Peter Clift for his assistance evaluating this paper.Attached Files
Published - grl52721.pdf
Supplemental Material - grl52721-sup-0001-Supp.doc
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Additional details
- Eprint ID
- 57573
- Resolver ID
- CaltechAUTHORS:20150515-152216867
- Created
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2015-05-15Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Seismological Laboratory, Division of Geological and Planetary Sciences